// from 08h to 17h (until 17:30) */30 8-17 * * * // from 08h to 17h, at number '5' (until 17:35) 5,30 8-17 * * *
// every 30 minutes */30 * * * * // it depends on the crontab version you are using // example: every 30 minutes at number '5' // mode 1 5,35 * * * * // mode 2 5/30 * * * *